Solid-phase phosphotriester approach

Miyoshi KI, Huang TH, Itakura K. Solid-phase synthesis of polynucleotides Synthesis of polynucleotides with defined sequences by the block coupling phosphotriester approach. Nucleic Acids Res 8 5491-5505, 1980. 

Sproat BS, Gait MJ. Solid-phase synthesis of oligodeoxyribonucleotides by the phosphotriester method. In Gait MJ, ed. Oligonucleotide Synthesis A Practical Approach. Oxford IRL Press Ltd, 1984 83-115. 

Although (1) has not been used in solid-phase oligonucleotide synthesis, another more stable arylsulfonyl derivative, l-(mesityl-sulfonyl)-3-nitro-l,2,4-triazole (MSNT), is commonly used in that strategy by the phosphotriester approach. ... 

The two most recent preparative approaches, the phosphoramidite and H-phosphonate routes, have, to my knowledge, not been used to any extent to prepare longer oligonucleotides in solution. Several papers describe the use of solution-synthesized blocks (mostly dimers prepared by the phosphotriester route) for solid-phase chain extension (56a e). The advantage of such blockwise support synthesis is the reduction of cycles and, thus, of overall time required for the preparation of longer chains. However, this may not lead to much decreased labor and expense because of prior block synthesis. Also the purifica-... 

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